US1821020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Foot attachment for pit frops or steel arches employed as colliery or mining roof supports
Assignee: Individual
•
Filing: 1930-07-08
•
Granted: 1931-09-01
•
Expires: 1950-07-08
Abstract
No abstract record available.
Inventors
- 👤 Mensforth Thomas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 06:40
CPC Classifications
E; E21; E21D; E21D15/00; E21D15/14; E21D15/16; E21D15/22
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1934-08-31 | 1935-03-02 | 1935-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1938-08-31 | 1939-03-02 | 1939-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1942-08-31 | 1943-03-02 | 1943-09-01 | $7700.00 | Window Closed / Lapsed |